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Molecular & Cell Biology

In experiments with mice, a team of scientists from the United States, Sweden and Japan has discovered that having a double dose of one protein is sufficient to change the normal balance of cells within the lining of the colon, thereby doubling the risk that a cancer-causing genetic mutation will trigger a tumor there. Roughly 10 percent of people have this double protein dose as well.

In the Feb. 24 online version of Science, the researchers report that mice engineered to have a double dose of insulin-like growth factor 2 (IGF2) develop more so-called precursor cells within the lining of the colon than normal mice. When these mice also carried a colon-cancer-causing genetic mutation, they developed twice as many tumors as those with normal IGF2 levels, the researchers report.

Microbiology

Scientists have found that the bacterium that causes dysentery uses a 'sword and shield' approach to cause infection.

According to research published today in Science, the team from Imperial College London and Institut Pasteur, Paris, found that shigella, the bacteria which causes dysentery, is able to invade cells, while stopping any response from the immune system.

They found that shigella was able to infect cells by using a secretion system to inject proteins into human cells, (the sword), while lipopolysaccharide (LPS) on the surface of the bacteria acts as a shield to protect the dysentery bacterium from being destroyed by the body's immune system.

AIDS & HIV

Mount Sinai School of Medicine researchers demonstrated that a gel applied in the vagina provides protection from both the human immunodeficiency virus (HIV) and the herpes simplex Virus. The study, presented at the 12th Conference on Retroviruses and Opportunistic Infections, is the first to show that a gel can retain anti-viral activity within the human vagina.

The study, which was funded by the National Institutes of Health (NIH) investigated the efficacy of PRO 2000, a topical microbicide under development by Indevus Pharmaceuticals, Inc.

Microbiology

Scientists know that injecting iron into some major regions of the oceans can stimulate the growth of diatoms and other phytoplankton, but something odd occurs as these tiny marine plants continue to grow. They begin to starve in the midst of plenty, acting as though iron, an essential nutrient, still is in short supply. Why this happens is unclear, but the answer could be that iron sets off a kind of chemical warfare in the marine ecosystem, according to University of Maine oceanographer Mark Wells. And diatoms may not always come out on top.

In collaboration with a large Japanese research program, Wells and a team of scientists from UMaine and other universities are studying the fate of iron in marine waters. Their findings could help determine the fate of something else, a controversial proposal to address the threat of global warming. The National Science Foundation and the U.S. Department of Energy are providing financial support.

Molecular & Cell Biology

The DNA tumor virus simian virus 40 produces the Large T antigen which inactivates two of the cell's most important cancer-preventing proteins, p53 and pRb. In a study published in the Journal of Biological Chemistry, researchers at the Fred Hutchinson Cancer Research Center report the discovery of an additional target for T antigen--a protein called Fbw7.

The Fbw7 gene is located in a chromosomal region that is deleted in up to 30% of human tumors. "Fbw7 is itself an important tumor suppressor which makes it an attractive choice for inactivation by Large T," explained Dr. Markus Welcker, the study's first author.

The research appears as the "Paper of the Week" in the March 4 issue of the Journal of Biological Chemistry, an American Society for Biochemistry and Molecular Biology journal.

Health & Medicine

Scientists at Joslin Diabetes Center have discovered one reason why infants with low birth weight have a high potential of developing type 2 diabetes later in life. In studies of mice, the researchers found that poor prenatal nutrition impairs the pancreas's ability to later secrete enough insulin in response to blood glucose.

"The bottom line is that if you don't have delivery of enough nutrients from the mother to the baby, the baby's pancreatic cells will be programmed abnormally," said principal investigator Mary-Elizabeth Patti, M.D., Assistant Investigator in Joslin's Research Section on Cellular and Molecular Physiology and Assistant Professor of Medicine at Harvard Medical School. "The effect doesn't show up until later on -- usually not until adolescence or adulthood.

General
GeneralFebruary 27, 2005 09:20 PM

Were I've been, you're asking yourself? Between fixing a computer (the power supply blew up), installing a new one (hint : AMD64 have a nice feature, Data Execution Prevention, which is supposed to prevent viruses from executing; however, when it cause the Windows XP installer to reboot without warning, I was a sad panda. Took me 5 hours to identify the problem and find a way to disable DEP), my parents visiting us, a concert with my girlfriend, restaurant, shopping... I found no time at all to update! I'm quite tired now, but don't worry, we still have enough energy to post news :)

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